A technology disclosed by this invention relates to a power management for a computer system, and more particularly, to a power management for each logical partition in a computer system which includes a storage system.
Logical partitioning technology has been proposed as a method of realizing a high-performance information processing system while suppressing increases in foot print, power consumption, and management cost of a computer system. Logical Partitioning technology realizes multiple virtual machines in a computer system by means of dividing resources of the computer system and allot them to each virtual machine. We can also call a virtual machine a logical partition. By controlling allocation of resources to each of the virtual machines, performance can be guaranteed for each of the virtual machines. An operating system may be installed in each virtual machine. The virtual machines can independently run, stop, do error handling, or the like. Thus, the logical partitioning technology enables a flexible operation of the computer system.
In recent years, in order to prevent from global warming, industrial products need to reduce their power consumption. Because of such a requirement, in computer systems, reduction in power consumption has been becoming an important performance measure.
U.S. 2004/0111596 discloses an exemplary technology of reducing power consumption in an environment where one computer is divided into a plurality of virtual machines. According to this technology, server resources not allocated to any logical partitions are powered off. Resource allocation is controlled so that an amount of resources not allocated to any logical partitions is maximum. Additionally, a physical disk not allocated to any logical partition is powered off.